The invention is directed to a strip deflection roller, especially a tension measuring roller or looper roller for matching tension in rolling stock between two roll stands for hot rolling and cold rolling of strip.
Tension measuring rollers or looper rollers are used in hot rolling mills and cold rolling mills, for example, between two four-high stands and normally serve for tension matching between stands. In cold rolling, the tension measuring roller is moved to a fixed position and, by means of the force transmitted to the tension measuring roller by the strip tension via the strip, tension matching is achieved by means of suitable measurement sensors by adapting the rolling speed of the stands. In hot rolling, looper rollers are used to form loops in the strip for tension matching, wherein the looper position, i.e., its height position, is a measure for the looped strip reserve between the stands. In matching the speeds of the stands, it is attempted to keep the strip reserve, and therefore the looper position, within a determined area.
It is impossible to correct the strip tension along the strip width in the tension measuring rollers and cylindrical looper rollers used in the prior art. Since regulation of profile and flatness is indispensable in modern rolling mills of the type described above, it is the object of the present invention to use the tension measuring rollers or looper rollers for matching tension in rolling stock between two roll stands also as means for regulating profile and flatness. This requires a special construction of the strip deflection rollers.
To meet this object, it is suggested according to the invention that the strip deflection roller comprises at least five adjacent disks which are mounted on a common eccentric shaft so as to be freely rotatable independently from one another, at most two of these disks being mounted concentric to the axis of rotation of the shaft, and the height positions of the rest of the disks can be changed for influencing the profile and regulating the flatness of the strip guided over the strip deflection roller by means of rotating the eccentric shaft.
The diameters of the disks can be identical or may vary. With appropriate selection of the disk diameter and eccentricity of the eccentric shaft, the outer contour of the strip deflection roller can be adjusted by rotation of the stepper motor continuously from a concave profile to a parallel profile to a convex profile, so that the flatness and, if required, the profile of the strip guided over the roller can be corrected.
It is advantageously provided that the eccentric shaft can be driven in rotation continuously by a stepper motor acting on the axle of the shaft.
According to the invention, for use in roll stands for cold rolling of strip, the strip deflection roller is moved to a fixed position relative to the strip which is deflected under tension and the desired flatness correction is adjusted by rotating the eccentric shaft axle. In this regard, the flatness correction is limited by the geometry of the strip deflection roller and the adjusted tension.
When the invention is applied in roll stands for the hot rolling of strip, the strip deflection roller is used as a looper roller, as it is called, and its height position is adjusted to compensate for speed differences in the two stands, the desired flatness correction likewise being adjusted by rotating the eccentric shaft axle.
Accordingly, in contrast to cold rolling mills, the strip deflection roller is not moved to a fixed position in the hot rolling mill, but, rather, by forming a strip reserve between two stands, serves as a looper for compensating for speed differences between the stands. As a result, there are variations in the height of the looper and differences in the relative elongation or strain depending on the looper height. These differences can be corrected by changing the strip deflection roller profile in continuous manner in that the stepper motor adjusts the appropriate strip deflection roller position by rotating the eccentric shaft.
In an advantageous construction of the invention, it is suggested that the strip deflection roller is used simultaneously as a tension measuring roller by outfitting it with suitable known measurement transmitters.
The invention is described in the following by means of an embodiment.